The invention relates to a cutting tool assembly having a replaceable spray nozzle housing.
Cutting tool assemblies for such applications as mining or road milling typically comprise a cutting tool, sometimes referred to as a cutting pick, rotatably mounted within a support block. The support block in turn is mounted onto a drum, chain or other body, typically by welding, which in turn is driven by a suitable drive means. A number of such support blocks carrying cutting tools are mounted onto said drum to continually mine and remove material such as coal, rock, concrete, asphalt or concrete. The material in the earth strata being mined or removed by the cutting tool is pulverized by the cutting picks as each tip is rotated about the drum or chain into contact with the earth strata. The material being mined or removed is pulverized by the impact of the pick and explodes in all directions. Some of the pulverized material collides against the support block and other cutting tool structure. The continual collision of pulverized material against the support block during operation causes abrasion and wear of the support block and any other components mounted on or near the support block.
It is also known to equip a cutting tool assembly with a spray nozzle for spraying fluid onto a cutting tool so as to reduce the potential for ignition of gases encountered during cutting or mining activities. These spray nozzles mounted on cutting tool support blocks are also benefical in suppressing dust particles that otherwise would be stirred up into the atmosphere during the operation of the cutting tool. U.S. Pat. No. 5,378,048, to Parrot, for example, discloses a water spray nozzle that is retained within a threaded bore of a pick box or support block using a resilient retaining ring. This nozzle is relatively complex in design and relatively costly to manufacture. Furthermore, the discharge end of the nozzle is contained within a bore drilled in the support block. Consequently, when the support block is sufficiently worn away, it can no longer house the nozzle; however the support block maintains its usefulness in holding the cutting pick. Despite this the support block and cutting tool assembly must be removed from the drum and a new support block having a new threaded bore for retaining a spray nozzle is attached to the drum. Support blocks are expensive themselves and attaching a new one to a drum is time consuming and disruptive of the mining operation. Typically a replacement support block must be manually welded onto the drum or chain, significantly hampering the efficeiency of the mining operation.
Siebenhofer et al.""s U.S. Pat. No. 5,498,069 discloses a cutting tool assembly including a spray nozzle in a bore of the support block adjacent to the cutting tool. When the support block is sufficiently worn away, it can no longer house the nozzle. Additionally the water passages disposed in Siebenhofer et al.""s support block for providing water to the nozzle are configured such that they cannot be drilled out once the pick support box is welded to a drum. As a result, when the passages become blocked, such as by calcium deposits, the cutting tool assembly is no longer useful for cutting operations that require a functioning spray nozzle.
It is an object of the invention to provide a new and improved cutting tool assembly having a support block and a replaceable spray nozzle housing mounted to the support block, wherein the spray nozzle housing is simple in design and relatively economical to manufacture.
In one embodiment of the invention, the cutting tool assembly comprises a support block having a cylindrical outlet portion. A replaceable unitary spray nozzle housing includes a base and upper spray nozzle housing portion. An inlet body portion extends downward from the base portion. The inlet portion of the replacement nozzle housing includes two separated collars on its exterior surface for forming a press fit seal with the support block cylindrical outlet portion. This press fit seal in combination with a fixing means such as a screw provides a method for quick and easy connection and disconnection of the nozzle housing from the support block.
The cutting tool assembly comprises a support block having first and second outer surfaces and first and second fluid passages. The first and second fluid passages communicate fluid between the first and second outer surface portions of the support block. The first and second fluid passages are in fluid communication with each other at the second outer surface. The replaceable spray nozzle housing inlet body portion is press fit into the bore of first fluid passage at first outer surface such that the spray nozzle housing is in fluid communication with the first fluid passage. The second fluid passage communicates with a conventional nozzle insert positioned near the first outer surface. The first and second passages both have straight-line axes that extend between the second outer surface portion and the first outer surface.
Advantageously, with such a straight-line configuration the first and second fluid passages can each be easily drilled in one machining step during manufacturing. The straight-line passage configurations also permits ease in cleaning debris such as calcium from the fluid passages so as to ensure maximum fluid flow therethrough.
While one embodiment of the new and improved cutting tool assembly is illustrated and disclosed, such disclosure should not be construed to limit the claims. It is anticipated that various modifications and alternative designs may be made without departing from the scope of the invention.